This invention relates generally to the field of gas downdraft cooking appliances and in particular to providing airflow paths for exhaust air, combustion air and cooling air. These airflow paths are concurrently induced by a downdraft exhaust blower system and are balanced so that any one of the airflows does not overcome the other two.
Jenn et al, in U.S. Pat. No. 3,367,320 issued Feb. 26, 1968, teach an electric countertop cooking unit having a centrally located downdraft blower system for capturing cooking byproducts and heated air and exhausting to atmosphere.
Davis, in U.S. Pat. No. 3,375,819 issued Apr. 2, 1968, shows a drop-in gas cooktop unit having provisions for air to enter the space between the cooktop and the bottom burner pan through openings in vertical side flanges. This provides combustion air for the pilot light and also provides some of the primary air for the burners. The convection airflow cools the combustion box and cooktop and carries away heat and gaseous combustion products from within the burner box.
Happel et al, in U.S. Pat. No. 3,444,805, issued May 20, 1969, also teach an electric downdraft unit especially for broiling meat articles. An airflow path is provided below a grease catching pan for cooling that pan.
Berlik et al, in U.S. Pat. No. 4,409,954 issued Oct. 18, 1983, disclose a gas downdraft range which utilizes modular cartridges to provide a grill unit or a surface burner unit. Each modular cartridge is a complete unit in itself and includes its own igniter system and gas burner. Combustion air enters the range compartments by way of apertures located in front of and behind the downdraft plenum opening. The combustion air enters the cartridges through a plurality of louvers formed in the sides of the cartridges. This system also provides for gathering exhaust air from above the cooking cartridges and drawing it into the downdraft plenum.
The prior art has thus shown the combining of cooling and combustion airflows and downdraft systems for inducing cooling airflow and for introducing combustion air to within a cooking cartridge. In some of these prior art constructions, the cooling function is either omitted or is not isolated from the combustion air. Also, in some systems, the downdraft air prevents combustion air from entering the burner box or even pulls fresh air from within the burner box. It is believed that there has been no showing in the prior art of the proposed combination which provides for substantially balanced cooling, combustion and exhaust airflows.